1998 Toyota 4Runner Owners Manual - Page 217

4RUNNER (1998) If the floor mat has a hole, then it is designed for use with a locking clip. Fix the floor mat and locking clip into the hole in the floor carpet. CAUTION Make sure the floor mat is properly placed on the floor carpet. If the floor mat slips and interferes with the movement of the pedals during driving, it may cause an accident.